build-sys: use -Og instead of -O0 to catch warnings

  $ touch src/core/dbus.c; make CFLAGS=-O0
  make --no-print-directory all-recursive
  Making all in .
    CC       src/core/libsystemd_core_la-dbus.lo
    CCLD     libsystemd-core.la

  $ touch src/core/dbus.c; make CFLAGS=-Og
  make --no-print-directory all-recursive
  Making all in .
    CC       src/core/libsystemd_core_la-dbus.lo
  src/core/dbus.c: In function 'init_registered_system_bus':
  src/core/dbus.c:798:18: warning: 'id' may be used uninitialized in this function [-Wmaybe-uninitialized]
           dbus_free(id);
                    ^
    CCLD     libsystemd-core.la

-Og Optimize debugging experience. -Og enables optimizations that do
not interfere with debugging. It should be the optimization level of
choice for the standard edit-compile-debug cycle, offering a
reasonable level of optimization while maintaining fast compilation
and a good debugging experience.

1 files changed, 1 insertions, 1 deletions

diff --git a/autogen.sh b/autogen.sh
index eeb0c1b5e..d0873422a 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -54,7 +54,7 @@ args="$args \
 fi
 
 if [ "x$1" = "xc" ]; then
-        ./configure CFLAGS='-g -O0' $args
+        ./configure CFLAGS='-g -Og' $args
         make clean
 else
         echo